In recent years, the development of selective herbicidal compounds has become of increasing commercial importance. Of particular importance is the development of ring and side chain halogenated phenylacetic acids, as they have been shown to have a particularly effective control of certain non-desirable weeds. U.S. Pat. No. 3,134,808 discloses several examples of chlorine substituted phenylacetic acids and their use as herbicides. A problem with the commercialization of these compounds has been, however, the expense of commercial preparation thereof and the attendant difficulties inherent in the known commercial processes for their preparation. Among the methods which have been advanced for the preparation of these compounds has been the chlorination of trihalophenylacetic acids, in the molten state, or, in an organic solvent resistant to halogenation; or, alternately by the chlorination of the corresponding substituted phenylacetonitrile to introduce chlorine atoms as desired into the alpha-position, followed by the controlled hydrolysis of the nitrile to the acid. Such methods, however, are complex and difficult to control and result in low yield products which are expensive to reproduce.
It is an object of the instant invention to provide useful intermediates for the preparation of substituted phenylacetic acids. It is also an object of this invention to produce a process for the production of substituted phenylacetic acids in high yields and high purity. Further, it is an object of the instant invention to provide a process for the preparation of intermediates useful in the production of substituted phenylacetic acids. It is still another object of this invention to provide a simple process for the production of substituted phenylacetic acid. These and other objects will become more apparent from the following discussion.